PROJECT SUMMARY The proposed R01 project (EPIC) examines whether a prenatal depression prevention intervention?Mothers and Babies (MB)?improves parenting practices and child self-regulation through 54 months of age. We build on an existing cluster randomized controlled trial that enrolled 874 diverse, low-income women from 36 home visiting (HV) programs. We anticipate 598 of these women will be eligible for EPIC (489 intervention, 109 control) and we will enroll an additional 260 control participants as part of this R01, for a total sample of 858. We will also enroll 429 fathers. Perinatal depression is consistently linked to poor parenting practices and poor child self-regulation. This project builds on previous work that has demonstrated MB?s effects on improving maternal mental health outcomes and will examine the intervention?s longer-term impact on parenting and child self-regulation from 30-54 months of age. Intervention participants will have received the six-week MB intervention delivered in a group format in addition to usual HV services while control participants will have only received HV services. Data collection for the R01 includes maternal self-report with all 858 participants every six months, beginning at 30 months postpartum and continuing until 54 months postpartum. An intensive sub- study of parenting and child development will occur at 36, 42, and 48 months for a subset of 460 participants (230 intervention, 230 control). Paternal self-report surveys will occur at 30, 42, and 54 months. There are three specific aims. First, we test the hypothesis that MB improves parenting and child self-regulatory skill acquisition through 54 months of age. We will use intent-to-treat as well as propensity score adjusted analysis. Second, we test hypotheses about the maternal mechanisms by which MB influences parenting and child self- regulation. We hypothesize that MB intervention effects will be mediated by core skills targeted by MB?in particular, increased awareness of thoughts and feelings and increases in mood regulation?as these cognitive-behavioral skills are deficient in mothers with depressive symptoms and compromise mothers? ability to engage in parenting practices that promote young children?s self-regulation. Third, we will examine fathers? and other key sociodemographic variables? role in moderating the impact of MB on mother?s parenting and the child?s self-regulation. The public health significance and innovation of this project is substantial. Addressing maternal mental health has been identified as a highly impactful enhancement to HV programs. If, as expected, we are able to generate a robust science base that precisely identifies mechanisms and outcomes impacted by the intervention in young children among our racially and ethnically diverse sample, HV programs currently using MB are likely to enhance their programmatic outcomes. Moreover, given the large number of HV programs that could adopt MB nationally, findings from this study can provide powerful data suggesting that MB become integrated into their core set of services.